A bridge to recovery: Acute amantadine prior to environmental enrichment after brain trauma augments cognitive benefit

Environmental enrichment (EE) facilitates motor and cognitive recovery after traumatic brain injury (TBI). Historically, EE has been provided immediately and continuously after TBI, but this paradigm does not model the clinic where rehabilitation is typically not initiated until after critical care. Yet, treating TBI early may facilitate recovery. Hence, we sought to provide amantadine (AMT) as a bridge therapy before commencing EE. It was hypothesized that bridging EE with AMT would augment motor and cognitive benefits. Anesthetized adult male rats received a cortical impact (2.8 mm deformation at 4 m/s) or sham surgery and then were housed in standard (STD) conditions where they received intraperitoneal AMT (10 mg/kg or 20 mg/kg) or saline vehicle (VEH; 1 mL/kg) beginning 24 h after surgery and once daily during the 6-day bridge phase or once daily for 19 days for the non-bridge groups (i.e., continuously STD-housed) to compare the effects of acute AMT plus EE vs. chronic AMT alone. Abbreviated EE, which was presented to closer emulate clinical rehabilitation (e.g., 6 h/day), began on day 7 for the AMT bridge and chronic EE groups. Motor (beam-walking) and cognition (acquisition of spatial learning and memory) were assessed on days 7-11 and 14-19, respectively. Cortical lesion volume and hippocampal cell survival were quantified on day 21. EE, whether provided in combination with VEH or AMT, and AMT (20 mg/kg) + STD, benefitted motor and cognition vs. the STD-housed VEH and AMT (10 mg/kg) groups (p < 0.05). The AMT (20 mg/kg) + EE group performed better than the VEH + EE, AMT (10 mg/kg) + EE, and AMT (20 mg/kg) + STD groups in the acquisition of spatial learning (p < 0.05) but did not differ in motor function (p > 0.05). All groups receiving EE exhibited decreased cortical lesion volumes and increased CA3 neuron survival relative to the STD-housed groups (p < 0.05) but did not differ from one another (p > 0.05). The added cognitive benefit achieved by bridging EE with AMT (20 mg/kg) supports the hypothesis that the temporal separation of combinational therapies is more effective after TBI.

Early Life Stress Negatively Impacts Spatial Learning Acquisition and Increases Hippocampal CA1 Microglial Activation After a Mild Traumatic Brain Injury in Adult Male Rats

Early life stress (ELS) affects neurogenesis and spatial learning, and increases neuroinflammation after a pediatric mild traumatic brain injury (mTBI). Previous studies have shown that ELS has minimal effects in juveniles but shows age-dependent effects in adults. Hence, we aimed to evaluate the effects of ELS in adult male rats after an mTBI. Maternal separation for 180 min per day (MS180) during the first 21 post-natal (P) days was used as the ELS model. At P110, the rats were subjected to a mild controlled cortical impact injury (2.6 mm) or sham surgery. Spatial learning was evaluated in the Morris water maze (MWM) 14 days after surgery and both microglial activation and neurogenesis were quantified. The results indicate that MS180 + mTBI, but not control (CONT) + mTBI, rats show deficiencies in the acquisition of spatial learning. mTBI led to comparable increases in microglial activation in both the hilus and cortical regions for both groups. However, MS180 + mTBI rats exhibited a greater increase in microglial activation in the ipsilateral CA1 hippocampus subfield compared with CONT + mTBI. Interestingly, for the contralateral CA1 region, this effect was observed exclusively in MS180 + mTBI. ELS and mTBI independently caused a decrease in hippocampal neurogenesis and this effect was not increased further in MS180 + mTBI rats. The findings demonstrate that ELS and mTBI synergistically affect cognitive performance and neuroinflammation, thus supporting the hypothesis that increased inflammation resulting from the combination of ELS and mTBI could underlie the observed effects on learning.

Efficacy of a music-based intervention in a preclinical model of traumatic brain injury: An initial foray into a novel and non-pharmacological rehabilitative therapy

Traumatic brain injury (TBI) causes neurobehavioral and cognitive impairments that negatively impact life quality for millions of individuals. Because of its pernicious effects, numerous pharmacological interventions have been evaluated to attenuate the TBI-induced deficits or to reinstate function. While many such pharmacotherapies have conferred benefits in the laboratory, successful translation to the clinic has yet to be achieved. Given the individual, medical, and societal burden of TBI, there is an urgent need for alternative approaches to attenuate TBI sequelae and promote recovery. Music based interventions (MBIs) may hold untapped potential for improving neurobehavioral and cognitive recovery after TBI as data in normal, non-TBI, rats show plasticity and augmented cognition. Hence, the aim of this study was to test the hypothesis that providing a MBI to adult rats after TBI would improve cognition, neurobehavior, and histological endpoints. Adult male rats received a moderate-to-severe controlled cortical impact injury (2.8 mm impact at 4 m/s) or sham surgery (n = 10-12 per group) and 24 h later were randomized to classical Music or No Music (i.e., ambient room noise) for 3 h/day from 19:00 to 22:00 h for 30 days (last day of behavior). Motor (beam-walk), cognitive (acquisition of spatial learning and memory), anxiety-like behavior (open field), coping (shock probe defensive burying), as well as histopathology (lesion volume), neuroplasticity (BDNF), and neuroinflammation (Iba1, and CD163) were assessed. The data showed that the MBI improved motor, cognitive, and anxiety-like behavior vs. No Music (p's < 0.05). Music also reduced cortical lesion volume and activated microglia but increased resting microglia and hippocampal BDNF expression. These findings support the hypothesis and provide a compelling impetus for additional preclinical studies utilizing MBIs as a potential efficacious rehabilitative therapy for TBI.

Antipsychotic Drugs: The Antithesis to Neurorehabilitation in Models of Pre-Clinical Traumatic Brain Injury

Sixty-nine million traumatic brain injuries (TBIs) are reported worldwide each year, and, of those, close to 3 million occur in the United States. In addition to neurobehavioral and cognitive deficits, TBI induces other maladaptive behaviors, such as agitation and aggression, which must be managed for safe, accurate assessment and effective treatment of the patient. The use of antipsychotic drugs (APDs) in TBI is supported by some expert guidelines, which suggests that they are an important part of the pharmacological armamentarium to be used in the management of agitation. Despite the advantages of APDs after TBI, there are significant disadvantages that may not be fully appreciated clinically during decision making because of the lack of a readily available updated compendium. Hence, the aim of this review is to integrate the existing findings and present the current state of APD use in pre-clinical models of TBI. The studies discussed were identified through PubMed and the University of Pittsburgh Library System search strategies and reveal that APDs, particularly those with dopamine2 (D2) receptor antagonism, generally impair the recovery process in rodents of both sexes and, in some instances, attenuate the potential benefits of neurorehabilitation. We believe that the compilation of findings represented by this exhaustive review of pre-clinical TBI + APD models can serve as a convenient source for guiding informed decisions by critical care clinicians and physiatrists contemplating APD use for patients exhibiting agitation.

Neuroprotective potential of intranasally delivered L-myc immortalized human neural stem cells in female rats after a controlled cortical impact injury

Efficacious stem cell-based therapies for traumatic brain injury (TBI) depend on successful delivery, migration, and engraftment of stem cells to induce neuroprotection. L-myc expressing human neural stem cells (LMNSC008) demonstrate an inherent tropism to injury sites after intranasal (IN) administration. We hypothesize that IN delivered LMNSC008 cells migrate to primary and secondary injury sites and modulate biomarkers associated with neuroprotection and tissue regeneration. To test this hypothesis, immunocompetent adult female rats received either controlled cortical impact injury or sham surgery. LMNSC008 cells or a vehicle were administered IN on postoperative days 7, 9, 11, 13, 15, and 17. The distribution and migration of eGFP-expressing LMNSC008 cells were quantified over 1 mm-thick optically cleared (CLARITY) coronal brain sections from TBI and SHAM controls. NSC migration was observed along white matter tracts projecting toward the hippocampus and regions of TBI. ELISA and Nanostring assays revealed a shift in tissue gene expression in LMNSC008 treated rats relative to controls. LMNSC008 treatment reduced expression of genes and pathways involved in inflammatory response, microglial function, and various cytokines and receptors. Our proof-of-concept studies, although preliminary, support the rationale of using intranasal delivery of LMNSC008 cells for functional studies in preclinical models of TBI and provide support for potential translatability in TBI patients.

Neuroprotective potential of intranasally delivered L-myc immortalized human neural stem cells in female rats after a controlled cortical impact injury

Efficacious stem cell-based therapies for traumatic brain injury (TBI) depend on successful delivery, migration, and engraftment of stem cells to induce neuroprotection. L-myc expressing human neural stem cells (LMNSC008) demonstrate an inherent tropism to injury sites after intranasal (IN) administration. We hypothesize that IN delivered LMNSC008 cells migrate to primary and secondary injury sites and modulate biomarkers associated with neuroprotection and tissue regeneration. To test this, immunocompetent adult female rats received a controlled cortical impact injury (CCI) or sham surgery. LMNSC008 cells or a vehicle (VEH) were administered IN on postoperative days 7, 9, 11, 13, 15, and 17. The distribution and migration of eGFP-expressing LMNSC008 cells were quantified over 1 mm-thick optically cleared (CLARITY) coronal brain sections from TBI and SHAM controls. NSC migration was observed along white matter tracts projecting toward the hippocampus and regions of TBI. ELISA and Nanostring assays revealed a shift in tissue gene expression in LMNSC008 treated rats relative to controls. LMNSC008 treatment reduced expression of genes and pathways involved in inflammatory response, microglial function, and various cytokines and receptors. The data demonstrate a robust proof-of-concept for LMNSC008 therapy for TBI and provides a strong rationale for IN delivery for translation in TBI patients.

Sustained attention performance deficits in the three-choice serial reaction time task in male and female rats after experimental brain trauma

Impaired attention is central to the cognitive deficits associated with long-term sequelae for many traumatic brain injury (TBI) survivors. Assessing complex sustained attention post-TBI is clinically-relevant and may provide reliable avenues towards developing therapeutic and rehabilitation targets in both males and females. We hypothesized that rats subjected to a moderate TBI will exhibit attentional deficits seen as reduced accuracy and increased distractibility in an operant 3-choice serial reaction time task (3-CSRT), designed as an analogue of the clinical continuous performance test. Upon reaching baseline of 70% accuracy at the 300 ms cue, adult male and female Sprague-Dawley rats were subjected to a controlled cortical impact (2.8 mm deformation at 4 m/s) or sham injury over the right parietal cortex. After two weeks of recovery, they were retested on the 3-CSRT for ten days. Dependent measures include percent accuracy (overall and for each of the three cue ports), percent omissions, as well as latency to instrumental poke and retrieve reward. Results demonstrate that both males and females displayed reduced percent accuracy and increased omissions when re-tested post-TBI on 3-CSRT compared to Sham rats and to their own pre-insult baseline (p's < 0.05). Performance accuracy was impaired consistently throughout the ten days of post-surgery re-testing, suggesting pronounced and long-lasting dysfunction in sustained attention processes. Deficits were specifically more pronounced when the cue was pseudorandomly presented in the left-side cue port (p < 0.05), mirroring clinical hemispatial neglect. These data demonstrate significant and persistent complex attention impairments in both sexes after TBI, rendering identifying efficient therapies for cognitive recovery as pivotal.

Enriching adult male rats prior to traumatic brain injury does not attenuate neurobehavioral or histological deficits

Environmental enrichment (EE) confers significant increases in neurobehavioral and cognitive recovery and decreases histological damage in various models of traumatic brain injury (TBI). However, despite EE's pervasiveness, little is known regarding its prophylactic potential. Thus, the goal of the current study was to determine whether enriching rats prior to a controlled cortical impact exerts protection as evidenced by attenuated injury-induced neurobehavioral and histological deficits relative to rats without prior EE. The hypothesis was that enrichment prior to TBI would be protective. After two weeks of EE or standard (STD) housing, anesthetized adult male rats received either a controlled cortical impact (2.8 mm deformation at 4 m/s) or sham injury and then were placed in EE or STD conditions. Motor (beam-walk) and cognitive (spatial learning) performance were assessed on post-operative days 1-5 and 14-18, respectively. Cortical lesion volume was quantified on day 21. The group that was housed in STD conditions before TBI and received post-injury EE performed significantly better in motor, cognitive, and histological outcomes vs. both groups in STD conditions regardless of whether having received pre-injury EE or not (p < 0.05). That no differences in any endpoint were revealed between the two STD-housed groups after TBI suggests that enriching rats prior to TBI does not attenuate neurobehavioral or histological deficits and therefore does not support the hypothesis.

Resuscitation with epinephrine worsens cerebral capillary no-reflow after experimental pediatric cardiac arrest: An in vivo multiphoton microscopy evaluation

Epinephrine is the principal resuscitation therapy for pediatric cardiac arrest (CA). Clinical data suggest that although epinephrine increases the rate of resuscitation, it fails to improve neurological outcome, possibly secondary to reductions in microvascular flow. We characterized the effect of epinephrine vs. placebo administered at resuscitation from pediatric asphyxial CA on microvascular and macrovascular cortical perfusion assessed using in vivo multiphoton microscopy and laser speckle flowmetry, respectively, and on brain tissue oxygenation (PbO₂), behavioral outcomes, and neuropathology in 16-18-day-old rats. Epinephrine-treated rats had a more rapid return of spontaneous circulation and brisk immediate cortical reperfusion during 1-3 min post-CA vs. placebo. However, at the microvascular level, epinephrine-treated rats had penetrating arteriole constriction and increases in both capillary stalling (no-reflow) and cortical capillary transit time 30-60 min post-CA vs. placebo. Placebo-treated rats had increased capillary diameters post-CA. The cortex was hypoxic post-CA in both groups. Epinephrine treatment worsened reference memory performance vs. shams. Hippocampal neuron counts did not differ between groups. Resuscitation with epinephrine enhanced immediate reperfusion but produced microvascular alterations during the first hour post-resuscitation, characterized by vasoconstriction, capillary stasis, prolonged cortical transit time, and absence of compensatory cortical vasodilation. Targeted therapies mitigating the deleterious microvascular effects of epinephrine are needed.

Environmental enrichment improves traumatic brain injury-induced behavioral phenotype and associated neurodegenerative process

Traumatic brain injury (TBI) causes persistent cognitive impairment and neurodegeneration. Environmental enrichment (EE) refers to a housing condition that promotes sensory and social stimulation and improves cognition and motor performance but the underlying mechanisms responsible for such beneficial effects are not well defined. In this study, anesthetized adult rats received either a moderate-to-severe controlled cortical impact (CCI) or sham surgery and then were housed in either EE or standard conditions. The results showed a significant increase in protein nitration and oxidation of lipids, impaired cognition and motor performance, and augmented N-methyl-d-aspartate receptor subtype-1 (NMDAR1) levels. However, EE initiated 24 h after CCI resulted in reduced oxidative insult and microglial activation and significant improvement in beam-balance/walk performance and both spatial learning and memory. We hypothesize that following TBI there is an upstream activation of NMDAR that promotes oxidative insult and an inflammatory response, thereby resulting in impaired behavioral functioning but EE may exert a neuroprotective effect via sustained downregulation of NMDAR1.

Chronic unpredictable stress during adolescence protects against adult traumatic brain injury-induced affective and cognitive deficits

Pre-clinical early-life stress paradigms model early adverse events in humans. However, the long-term behavioral consequences of early-life adversities after traumatic brain injury (TBI) in adults have not been examined. In addition, endocannabinoids may protect against TBI neuropathology. Hence, the current study assessed the effects of adverse stress during adolescence on emotional and cognitive performance in rats sustaining a TBI as adults, and how cannabinoid receptor 1 (CB1) activation impacts the outcome. On postnatal days (PND) 30-60, adolescent male rats were exposed to four weeks of chronic unpredictable stress (CUS), followed by four weeks of no stress (PND 60-90), or no stress at any time (Control), and then anesthetized and provided a cortical impact of moderate severity (2.8 mm tissue deformation at 4 m/s) or sham injury. TBI and Sham rats (CUS and Control) were administered either arachidonyl-2'-chloroethylamide (ACEA; 1 mg/kg, i.p.), a CB1 receptor agonist, or vehicle (VEH; 1 mL/kg, i.p.) immediately after surgery and once daily for 7 days. Anxiety-like behavior was assessed in an open field test (OFT) and learning and memory in novel object recognition (NOR) and Morris water maze (MWM) tasks. No differences were revealed among the Sham groups in any behavioral assessment and thus the groups were pooled. In the ACEA and VEH-treated TBI groups, CUS increased exploration in the OFT, enhanced NOR focus, and decreased the time to reach the escape platform in the MWM, suggesting decreased anxiety and enhanced learning and memory relative to the Control group receiving VEH (p < 0.05). ACEA also enhanced NOR and MWM performance in the Control + TBI group (p < 0.05). These data suggest that 4 weeks of CUS provided during adolescence may provide protection against TBI acquired during adulthood and/or induce adaptive behavioral responses. Moreover, CB1 receptor agonism produces benefits after TBI independent of CUS protection.

Traumatic injury compromises nucleocytoplasmic transport and leads to TDP-43 pathology

Traumatic brain injury (TBI) is a predisposing factor for many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and chronic traumatic encephalopathy (CTE). Although defects in nucleocytoplasmic transport (NCT) is reported ALS and other neurodegenerative diseases, whether defects in NCT occur in TBI remains unknown. We performed proteomic analysis on Drosophila exposed to repeated TBI and identified resultant alterations in several novel molecular pathways. TBI upregulated nuclear pore complex (NPC) and nucleocytoplasmic transport (NCT) proteins as well as alter nucleoporin stability. Traumatic injury disrupted RanGAP1 and NPC protein distribution in flies and a rat model and led to coaggregation of NPC components and TDP-43. In addition, trauma-mediated NCT defects and lethality are rescued by nuclear export inhibitors. Importantly, genetic upregulation of nucleoporins in vivo and in vitro triggered TDP-43 cytoplasmic mislocalization, aggregation, and altered solubility and reduced motor function and lifespan of animals. We also found NUP62 pathology and elevated NUP62 concentrations in postmortem brain tissues of patients with mild or severe CTE as well as co-localization of NUP62 and TDP-43 in CTE. These findings indicate that TBI leads to NCT defects, which potentially mediate the TDP-43 pathology in CTE.

Intranasally Administered L-Myc-Immortalized Human Neural Stem Cells Migrate to Primary and Distal Sites of Damage after Cortical Impact and Enhance Spatial Learning

As the success of stem cell-based therapies is contingent on efficient cell delivery to damaged areas, neural stem cells (NSCs) have promising therapeutic potential because they inherently migrate to sites of central nervous system (CNS) damage. To explore the possibility of NSC-based therapy after traumatic brain injury (TBI), isoflurane-anesthetized adult male rats received a controlled cortical impact (CCI) of moderate severity (2.8 mm deformation at 4 m/s) or sham injury (i.e., no cortical impact). Beginning 1-week post-injury, the rats were immunosuppressed and 1 × 106 human NSCs (LM-NS008.GFP.fLuc) or vehicle (VEH) (2% human serum albumen) were administered intranasally (IN) on post-operative days 7, 9, 11, 13, 15, and 17. To evaluate the spatial distributions of the LM-NSC008 cells, half of the rats were euthanized on day 25, one day after completion of the cognitive task, and the other half were euthanized on day 46. 1 mm thick brain sections were optically cleared (CLARITY), and volumes were imaged by confocal microscopy. In addition, LM-NSC008 cell migration to the TBI site by immunohistochemistry for human-specific Nestin was observed at day 39. Acquisition of spatial learning was assessed in a well-established Morris water maze task on six successive days beginning on post-injury day 18. IN administration of LM-NSC008 cells after TBI (TBI + NSC) significantly facilitated spatial learning relative to TBI + VEH rats (p < 0.05) and had no effect on sham + NSC rats. Overall, these data indicate that IN-administered LM-NSC008 cells migrate to sites of TBI damage and that their presence correlates with cognitive improvement. Future studies will expand on these preliminary findings by evaluating other LM-NSC008 cell dosing paradigms and evaluating mechanisms by which LM-NSC008 cells contribute to cognitive recovery.

Preclinical neurorehabilitation with environmental enrichment confers cognitive and histological benefits in a model of pediatric asphyxial cardiac arrest

Pediatric asphyxial cardiac arrest (ACA) often leaves children with physical, cognitive, and emotional disabilities that affect overall quality of life, yet rehabilitation is neither routinely nor systematically provided. Environmental enrichment (EE) is considered a preclinical model of neurorehabilitation and thus we sought to investigate its efficacy in our established model of pediatric ACA. Male Sprague-Dawley rat pups (post-natal day 16-18) were randomly assigned to ACA (9.5 min) or Sham injury. After resuscitation, the rats were assigned to 21 days of EE or standard (STD) housing during which time motor, cognitive, and anxiety-like (i.e., affective) outcomes were assessed. Hippocampal CA1 cells were quantified on post-operative day-22. Both ACA + STD and ACA + EE performed worse on beam-balance vs. Sham controls (p < 0.05) and did not differ from one another overall (p > 0.05); however, a single day analysis on the last day of testing revealed that the ACA + EE group performed better than the ACA + STD group (p < 0.05) and did not differ from the Sham controls (p > 0.05). Both Sham groups performed better than ACA + STD (p < 0.05) but did not differ from ACA + EE (p > 0.05) in the open field test. Spatial learning and declarative memory were improved and CA1 neuronal loss was attenuated in the ACA + EE vs. ACA + STD group (p < 0.05). Collectively, the data suggest that providing rehabilitation after pediatric ACA can reduce histopathology and improve motor and cognitive ability.

Paths to Successful Translation of New Therapies for Severe Traumatic Brain Injury in the Golden Age of Traumatic Brain Injury Research: A Pittsburgh Vision

New neuroprotective therapies for severe traumatic brain injury (TBI) have not translated from pre-clinical to clinical success. Numerous explanations have been suggested in both the pre-clinical and clinical arenas. Coverage of TBI in the lay press has reinvigorated interest, creating a golden age of TBI research with innovative strategies to circumvent roadblocks. We discuss the need for more robust therapies. We present concepts for traditional and novel approaches to defining therapeutic targets. We review lessons learned from the ongoing work of the pre-clinical drug and biomarker screening consortium Operation Brain Trauma Therapy and suggest ways to further enhance pre-clinical consortia. Biomarkers have emerged that empower choice and assessment of target engagement by candidate therapies. Drug combinations may be needed, and it may require moving beyond conventional drug therapies. Precision medicine may also link the right therapy to the right patient, including new approaches to TBI classification beyond the Glasgow Coma Scale or anatomical phenotyping-incorporating new genetic and physiologic approaches. Therapeutic breakthroughs may also come from alternative approaches in clinical investigation (comparative effectiveness, adaptive trial design, use of the electronic medical record, and big data). The full continuum of care must also be represented in translational studies, given the important clinical role of pre-hospital events, extracerebral insults in the intensive care unit, and rehabilitation. TBI research from concussion to coma can cross-pollinate and further advancement of new therapies. Misconceptions can stifle/misdirect TBI research and deserve special attention. Finally, we synthesize an approach to deliver therapeutic breakthroughs in this golden age of TBI research.

Early Life Stress Preceding Mild Pediatric Traumatic Brain Injury Increases Neuroinflammation but Does Not Exacerbate Impairment of Cognitive Flexibility during Adolescence

Early life stress (ELS) followed by pediatric mild traumatic brain injury (mTBI) negatively impacts spatial learning and memory and increases microglial activation in adolescent rats, but whether the same paradigm negatively affects higher order executive function is not known. Hence, we utilized the attentional set-shifting test (AST) to evaluate executive function (cognitive flexibility) and to determine its relationship with neuroinflammation and hypothalamic-pituitary-adrenal (HPA) axis activity after pediatric mTBI in male rats. ELS was induced via maternal separation for 180 min per day (MS180) during the first 21 post-natal (P) days, while controls (CONT) were undisturbed. At P21, fully anesthetized rats received a mild controlled cortical impact (2.2 mm tissue deformation at 4 m/sec) or sham injury. AST was evaluated during adolescence on P35-P40 and cytokine expression and HPA activity were analyzed on P42. The data indicate that pediatric mTBI produced a significant reversal learning deficit on the AST versus sham (p < 0.05), but that the impairment was not exacerbated further by MS180. Additionally, ELS produced an overall elevation in set-loss errors on the AST, and increased hippocampal interleukin (IL)-1β expression after TBI. A significant correlation was observed in executive dysfunction and IL-1β expression in the ipsilateral pre-frontal cortex and hippocampus. Although the combination of ELS and pediatric mTBI did not worsen executive function beyond that of mTBI alone (p > 0.05), it did result in increased hippocampal neuroinflammation relative to mTBI (p < 0.05). These findings provide important insight into the susceptibility to incur alterations in cognitive and neuroimmune functioning after stress exposure and TBI during early life.

Disruption of basal forebrain cholinergic neurons after traumatic brain injury does not compromise environmental enrichment-mediated cognitive benefits

Environmental enrichment (EE) attenuates traumatic brain injury (TBI)-induced loss of medial septal (MS) choline acetyltransferase (ChAT)-cells and enhances spatial learning and memory vs. standard (STD) housing. Whether basal forebrain cholinergic neurons (BFCNs) are important mediators of EE-induced benefits after TBI requires further investigation. Anesthetized female rats were randomly assigned to intraseptal infusions of the immunotoxin 192-IgG-saporin (SAP; 0.22 μg in 1.0 μL) or vehicle (VEH; 1.0 μL IgG) followed immediately by a cortical impact (2.8 mm deformation depth at 4 m/s) or sham injury and divided into EE and STD housing. Spatial learning and memory retention were assessed on post-operative days 14-19. MS ChAT⁺ cells were quantified at 3 weeks. SAP significantly reduced ChAT⁺ cells in both the EE and STD groups. Cognitive performance was improved in the EE groups, regardless of VEH or SAP infusion, vs. the STD-housed groups (p's < 0.05). No cognitive differences were revealed between the TBI + EE + SAP and TBI + EE + VEH groups (p > 0.05) or between the TBI + STD + SAP and TBI + STD + VEH groups (p > 0.05). These data show that despite significant MS ChAT⁺ cell loss, the EE-mediated benefit in cognitive recovery is not compromised.

Early life stress increases vulnerability to the sequelae of pediatric mild traumatic brain injury

Early life stress (ELS) is a risk factor for many psychopathologies that happen later in life. Although stress can occur in cases of child abuse, studies on non-accidental brain injuries in pediatric populations do not consider the possible increase in vulnerability caused by ELS. Hence, we sought to determine whether ELS increases the effects of pediatric mild traumatic brain injury (mTBI) on cognition, hippocampal inflammation, and plasticity. Male rats were subjected to maternal separation for 180 min per day (MS180) or used as controls (CONT) during the first 21 post-natal (P) days. At P21 the rats were anesthetized with isoflurane and subjected to a mild controlled cortical impact or sham injury. At P32 the rats were injected with the cell proliferation marker bromodeoxyuridine (BrdU, 500 mg/kg), then evaluated for spatial learning and memory in a water maze (P35-40) and sacrificed for quantification of Ki67⁺, BrdU⁺ and Iba1⁺ (P42). Neither MS180 nor mTBI impacted cognitive outcome when provided alone but their combination (MS180 + mTBI) decreased spatial learning and memory relative to Sham controls (p < .01). mTBI increased microglial activation and affected BrdU⁺ cell survival in the ipsilateral hippocampus without affecting proliferation rates. However, only MS180 + mTBI increased microglial activation in the area adjacent to the injury and the contralateral CA1 hippocampal subfield, and decreased cell proliferation in the ipsilateral neurogenic niche. Overall, the data show that ELS increases the vulnerability to the sequelae of pediatric mTBI and may be mediated by increased neuroinflammation.

Environmental enrichment and amantadine confer individual but nonadditive enhancements in motor and spatial learning after controlled cortical impact injury

Environmental enrichment (EE) and amantadine (AMT) enhance motor and cognitive outcome after experimental traumatic brain injury (TBI). However, there are no data on the effects of combining these two therapies. Hence, the aim of the current study was to combine EE and AMT after TBI to determine if their net effect further enhances motor and cognitive performance. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily administration of AMT (20 mg/kg; i.p.) or saline vehicle (VEH, 1 mL/kg; i.p.) beginning 24 h after injury for 19 days. Motor and cognitive function were assessed on post-surgical days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups regardless of therapy, so the data were pooled. EE, AMT, and their combination (EE + AMT) improved beam-balance, but only EE and EE + AMT enhanced beam-walking. All three treatment paradigms improved spatial learning and memory relative to the VEH-treated STD controls (p < 0.05). No differences were revealed between the EE groups, regardless of treatment, but both were better than the AMT-treated STD group on beam-walking and spatial learning (p < 0.05). Both EE groups equally reduced cortical lesion volume relative to the STD-housed AMT and VEH groups (p < 0.05). The results indicate that although beneficial on their own, EE + AMT do not provide additional benefits after TBI. It is important to note that the lack of additive effects using the current treatment and behavioral protocols does not detract from the benefits of each individual therapy. The findings provide insight for future combination studies.

The aquaporin-4 inhibitor AER-271 blocks acute cerebral edema and improves early outcome in a pediatric model of asphyxial cardiac arrest

BACKGROUND

Cerebral edema after cardiac arrest (CA) is associated with increased mortality and unfavorable outcome in children and adults. Aquaporin-4 mediates cerebral water movement and its absence in models of ischemia improves outcome. We investigated early and selective pharmacologic inhibition of aquaporin-4 in a clinically relevant asphyxial CA model in immature rats in a threshold CA insult that produces primarily cytotoxic edema in the absence of blood-brain barrier permeability.

METHODS

Postnatal day 16-18 Sprague-Dawley rats were studied in our established 9-min asphyxial CA model. Rats were randomized to aquaporin-4 inhibitor (AER-271) vs vehicle treatment, initiated at return of spontaneous circulation. Cerebral edema (% brain water) was the primary outcome with secondary assessments of the Neurologic Deficit Score (NDS), hippocampal neuronal death, and neuroinflammation.

RESULTS

Treatment with AER-271 ameliorated early cerebral edema measured at 3 h after CA vs vehicle treated rats. This treatment also attenuated early NDS. In contrast to rats treated with vehicle after CA, rats treated with AER-271 did not develop significant neuronal death or neuroinflammation as compared to sham.

CONCLUSION

Early post-resuscitation aquaporin-4 inhibition blocks the development of early cerebral edema, reduces early neurologic deficit, and blunts neuronal death and neuroinflammation post-CA.

Aripiprazole and environmental enrichment independently improve functional outcome after cortical impact injury in adult male rats, but their combination does not yield additional benefits

Typical antipsychotic drugs (APDs) with D₂antagonistic properties impede functional outcome after experimental traumatic brain injury (TBI) and reduce the effectiveness of environmental enrichment (EE). Here we test the hypothesis that aripiprazole (ARIP), an atypical APD with partial D₂and 5-HT_1Areceptor agonist activities will improve recovery after TBI and when combined with EE will further enhance the benefits. Anesthetized adult male rats received either a controlled cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily intraperitoneal injections of ARIP (0.1 mg/kg) or vehicle (VEH; 1.0 mL/kg) beginning 24 h after injury for 19 days. Motor (beam-walking time and beam-walk score) and cognitive (acquisition of spatial learning and memory) outcomes were assessed on post-operative days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups, regardless of housing or treatment, so the data were pooled. The SHAM group performed better than all TBI groups on motor and spatial learning (p < 0.05) but did not differ from either EE group on memory retention. Regarding TBI, both EE groups improved motor and cognitive outcomes vs. the VEH-treated STD group (p < 0.05) but did not differ from one another (p > 0.05). The ARIP-treated STD group performed better than the VEH-treated STD group on beam-walk score and spatial learning (p < 0.05), but not beam-walking time or memory retention (p > 0.05). Cortical lesion volume was smaller in all treated groups compared to the TBI + STD + VEH group (p < 0.05). The data replicate previous work and extend the findings by demonstrating that 1) ARIP promotes recovery after TBI, but combining treatments does not yield additional benefits, which is contrary to the hypothesis, and 2) unlike APDs that exhibit D₂ receptor antagonism, ARIP does not impede rehabilitation (i.e., EE).

Intermittent Administration of Haloperidol after Cortical Impact Injury Neither Impedes Spontaneous Recovery Nor Attenuates the Efficacy of Environmental Enrichment

The administration of haloperidol (HAL) once-daily for 19 days after experimental traumatic brain injury (TBI) impedes recovery and attenuates the efficacy of environmental enrichment (EE). However, it is unknown how intermittent administration of HAL affects the recovery process when paired with EE. Addressing the uncertainty is relevant because daily HAL is not always warranted to manage TBI-induced agitation in the clinic, and indeed intermittent therapy may be a more common approach. Hence, the aim of the study was to test the hypothesis that intermittent HAL would neither impair recovery in standard (STD)-housed controls nor attenuate the efficacy of EE. Anesthetized adult male rats received a cortical impact or sham injury and then were housed in STD or EE conditions. Beginning 24 h later, HAL (0.5 mg/kg; intraperitoneally [i.p.]) was administered either once-daily for 19 days or once every other day, whereas vehicle (VEH; 1 mL/kg; i.p.) was administered once daily. Motor performance and cognition were assessed on post-injury days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. SHAM controls performed better than all TBI groups on motor and spatial learning [p < 0.05], but did not differ from the TBI + EE + daily VEH group on memory retention [p > 0.05]. The TBI + EE + daily VEH and TBI + EE + intermittent HAL groups did not differ from one another on beam-walk or spatial learning [p > 0.05], and both performed better than all other TBI groups [p < 0.05]. In contrast, the TBI + STD + daily HAL group performed worse than all TBI groups on spatial learning [p < 0.05]. No difference in any endpoint was revealed between the TBI + STD + intermittent HAL and TBI + STD + daily VEH groups [p > 0.05]. The results support the hypothesis that HAL is not detrimental when provided intermittently. If translatable to the clinic, intermittent HAL may be used to control TBI-induced agitation without negatively affecting spontaneous recovery or rehabilitative efficacy.

Delayed and Abbreviated Environmental Enrichment after Brain Trauma Promotes Motor and Cognitive Recovery That Is Not Contingent on Increased Neurogenesis

Environmental enrichment (EE) confers motor and cognitive recovery in pre-clinical models of traumatic brain injury (TBI), and neurogenesis has been attributed to mediating the benefits. Whether that ascription is correct has not been fully investigated. Hence, the goal of the current study is to further clarify the possible role of learning-induced hippocampal neurogenesis on functional recovery after cortical impact or sham injury by utilizing two EE paradigms (i.e., early + continuous, initiated immediately after TBI and presented 24 h/day; and delayed + abbreviated, initiated 4 days after TBI for 6 h/day) and comparing them to one another as well as to standard (STD) housed controls. Motor and cognitive performance was assessed on post-operative Days 1-5 and 14-19, respectively, for the STD and early + continuous EE groups and on Days 4-8 and 17-22, for the delayed + abbreviated EE groups. Rats were injected with bromodeoxyuridine (BrdU, 500 mg/ kg; intraperitoneally) for 3 days (12 h apart) before cognitive training and sacrificed 1 week later for quantification of BrdU+ and doublecortin (DCX+) labeled cells. Both early + continuous and delayed + abbreviated EE promoted motor and cognitive recovery after TBI, relative to STD (p < 0.05), and did not differ from one another (p > 0.05). However, only early + continuous EE increased DCX+ cells beyond the level of STD-housed controls (p < 0.05). No effect of EE on non-injured controls was observed. Based on these data, two novel conclusions emerged. First, EE does not need to be provided early and continuously after TBI to confer benefits, which lends credence to the delayed + abbreviated EE paradigm as a relevant pre-clinical model of neurorehabilitation. Second, the functional recovery observed after TBI in the delayed + abbreviated EE paradigm is not contingent on increased hippocampal neurogenesis. Future studies will elucidate alternate viable mechanisms mediating the benefits induced by EE.

Dose-dependent neurorestorative effects of amantadine after cortical impact injury

Numerous pharmacotherapies have been evaluated after experimental traumatic brain injury (TBI). While amantadine (AMT) has shown potential for clinical efficacy, the few studies on its effectiveness have been mixed. It is possible that suboptimal dosing, due to the evaluation of only one dose, may be causing the discrepancies in outcomes. Hence, the goal of the current study was to conduct a dose response of AMT after TBI to determine an optimal behavioral benefit. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to receive once daily intraperitoneally injections of AMT (10, 20, or 40 mg/kg) or saline vehicle (VEH, 1 mL/kg) commencing 24 h after injury for 19 days. Motor and cognitive function were assessed on post-operative days 1-5 and 14-19, respectively. There were no statistical differences among the sham groups treated with AMT or VEH so the data were pooled. AMT (20 mg/kg) facilitated beam-balance recovery and spatial learning relative to VEH-treated controls (p < 0.05). No other doses of AMT were effective. These results indicate that dosing should be carefully considered when assessing the effects of pharmacotherapies after TBI so that potential benefits are not inadvertently missed.

Systemic administration of donepezil attenuates the efficacy of environmental enrichment on neurobehavioral outcome after experimental traumatic brain injury

BACKGROUND

The acetylcholinesterase inhibitor (AChEI) donepezil (DON) is recommended as a potential treatment for cognition after clinical traumatic brain injury (TBI) and therefore may be prescribed as an adjunct therapy during rehabilitation. However, a dose-response study evaluating DON after a controlled cortical impact (CCI) injury in rats did not reveal cognitive benefits.

OBJECTIVE

The aim of this study was to determine the effect of DON on behavioral and histological outcome when combined with environmental enrichment (EE), a preclinical model of neurorehabilitation. It was hypothesized that the combined treatments would produce a synergistic effect yielding improved recovery over neurorehabilitation alone.

METHODS

Isoflurane-anesthetized adult male rats received a CCI or sham injury and then were randomly assigned to EE or standard (STD) housing plus systemic injections of DON (0.25 mg/kg) or vehicle (VEH; 1.0 mL/kg saline) once daily for 19 days beginning 24 hr after injury. Function was assessed by established motor and cognitive tests on post-injury days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 19.

RESULTS

DON was ineffective when administered alone. In contrast, EE conferred significant motor and cognitive benefits, and reduced cortical lesion volume vs. STD (p < 0.05). Combining the therapies weakened the efficacy of rehabilitation as revealed by diminished motor and cognitive recovery in the TBI+EE+DON group vs. the TBI+EE+VEH group (p < 0.05).

CONCLUSION

These data replicate previous findings showing that EE is beneficial and DON is ineffective after CCI and add to the literature a novel and unpredicted finding that supports neither the hypothesis nor the use of DON for TBI. Investigation of other AChEIs after CCI injury is necessary to gain further insight into the value of this therapeutic strategy.

Spontaneous recovery after controlled cortical impact injury is not impeded by intermittent administration of the antipsychotic drug risperidone

Several preclinical studies have reported that daily administration of the antipsychotic drug (APD) risperidone (RISP) impedes recovery after traumatic brain injury (TBI). However, it is not known whether intermittent dosing would produce similar deleterious effects. The relevance of providing APDs intermittently is that not all patients in rehabilitation require daily treatments to manage TBI-induced agitation. Hence, the goal of the current study was to test the hypothesis that intermittent (vs. daily) administration of RISP would be less disturbing to motor and cognitive recovery after TBI. Anesthetized adult male rats were subjected to either a cortical impact of moderate severity or sham injury and then were randomly assigned to groups receiving intraperitoneal injections of vehicle (VEH; 1.0 mL/kg) or RISP (0.45 mg/kg) 1x, 3x, or 7x per week until the completion of behavioral testing, which consisted of motor and cognitive assessments on post-operative days 1-5 and 14-19, respectively. The group receiving RISP 7x week exhibited greater motor and cognitive impairment compared to those receiving RISP 1x or 3x per week, or VEH [p<0.05]. Moreover, no differences were observed between the intermittent RISP groups vs. VEH [p>0.05], which supports the hypothesis. A potential clinical ramification is that RISP may be safe to manage agitation after TBI, but only when used sparingly.

Preclinical Models of Traumatic Brain Injury: Emerging Role of Glutamate in the Pathophysiology of Depression

More than 10 million people worldwide incur a traumatic brain injury (TBI) each year, with two million cases occurring in the United States. TBI survivors exhibit long-lasting cognitive and affective sequelae that are associated with reduced quality of life and work productivity, as well as mental and emotional disturbances. While TBI-related disabilities often manifest physically and conspicuously, TBI has been linked with a "silent epidemic" of psychological disorders, including major depressive disorder (MDD). The prevalence of MDD post-insult is approximately 50% within the 1st year. Furthermore, given they are often under-reported when mild, TBIs could be a significant overall cause of MDD in the United States. The emergence of MDD post-TBI may be rooted in widespread disturbances in the modulatory role of glutamate, such that glutamatergic signaling becomes excessive and deleterious to neuronal integrity, as reported in both clinical and preclinical studies. Following this acute glutamatergic storm, regulators of glutamatergic function undergo various manipulations, which include, but are not limited to, alterations in glutamatergic subunit composition, release, and reuptake. This review will characterize the glutamatergic functional and signaling changes that emerge and persist following experimental TBI, utilizing evidence from clinical, molecular, and rodent behavioral investigations. Special care will be taken to speculate on how these manipulations may correlate with the development of MDD following injury in the clinic, as well as pharmacotherapies to date. Indisputably, TBI is a significant healthcare issue that warrants discovery and subsequent refinement of therapeutic strategies to improve neurobehavioral recovery and mental health.

Elucidating opportunities and pitfalls in the treatment of experimental traumatic brain injury to optimize and facilitate clinical translation

The aim of this review is to discuss the research presented in a symposium entitled "Current progress in characterizing therapeutic strategies and challenges in experimental CNS injury" which was presented at the 2016 International Behavioral Neuroscience Society annual meeting. Herein we discuss diffuse and focal traumatic brain injury (TBI) and ensuing chronic behavioral deficits as well as potential rehabilitative approaches. We also discuss the effects of stress on executive function after TBI as well as the response of the endocrine system and regulatory feedback mechanisms. The role of the endocannabinoids after CNS injury is also discussed. Finally, we conclude with a discussion of antipsychotic and antiepileptic drugs, which are provided to control TBI-induced agitation and seizures, respectively. The review consists predominantly of published data.

Spontaneous recovery of traumatic brain injury-induced functional deficits is not hindered by daily administration of lorazepam

Agitation and aggression are common sequelae of traumatic brain injury (TBI) and pose a challenge to physicians and other health providers during acute patient care and subsequent neurorehabilitation. Antipsychotic drugs (APDs) are routinely administered to manage TBI patients displaying such maladaptive behaviors despite several clinical and preclinical studies demonstrating that they hinder recovery. A potentially viable alternative to APDs may be the benzodiazepines, which have differing mechanisms of action. Hence, the aim of the study was to test the hypothesis that lorazepam (LOR) would not impede recovery after TBI. Anesthetized adult male rats received a cortical impact or sham injury and then were intraperitoneally administered LOR (0.1mg/kg, 1.0mg/kg, or 2.0mg/kg) or vehicle (VEH; 1mL/kg) commencing 24-h after surgery and once daily for 19days. Motor and cognitive outcomes were assessed on post-operative days 1-5 and 14-19, respectively. No differences were revealed among the four sham control groups and thus they were pooled into one inclusive SHAM group. The SHAMs performed better than all TBI groups on all assessments (p<0.05). Regarding TBI, the 2.0mg/kg LOR group performed better than the VEH and 0.1mg/kg or 1.0mg/kg LOR groups on every task (p<0.05); no differences were observed among the latter three groups on any endpoint (p>0.05). Overall, these preclinical behavioral data support the hypothesis and reveal a therapeutic benefit with the higher dose of LOR. The findings suggest that LOR may be an alternative, to APDs, for controlling agitation without compromising spontaneous recovery and perhaps could afford a dual benefit by also promoting therapeutic efficacy.

Rehabilitative Success After Brain Trauma by Augmenting a Subtherapeutic Dose of Environmental Enrichment With Galantamine

BACKGROUND

Environmental enrichment (EE) confers benefits after traumatic brain injury (TBI) when provided daily for > 6 hours, but not 2 or 4 hours, which more accurately reflects the daily amount of clinical rehabilitation. The lack of benefit with sub-therapeutic EE suggests that augmentation with galantamine (GAL), which enhances cognition after TBI, may be indicated to confer benefits.

OBJECTIVE

To test the hypothesis that 2 and 4 hours of EE paired with GAL will provide benefits comparable to 24 hours of EE alone. Moreover, all EE groups will perform better than the standard (STD)-housed GAL group.

METHODS

Anesthetized rats received a TBI or sham injury and then were randomized to receive intraperitoneal injections of GAL (2 mg/kg) or saline vehicle (VEH; 1 mL/kg) beginning 24 hours after surgery and once daily while receiving EE for 2, 4, or 24 hours. Motor and cognitive assessments were conducted on postoperative days 1-5 and 14-19, respectively.

RESULTS

Motor function was significantly improved in the TBI + 24-hour EE group versus the TBI + STD + VEH and TBI + STD + GAL groups ( P < .05). Cognitive performance was enhanced in all EE groups as well as in the TBI + STD + GAL versus TBI + STD + VEH ( P < .05). Moreover, the 2- and 4-hour EE groups receiving GAL did not differ from the 24-hour EE group ( P > .05) and performed better than GAL alone ( P < .05).

CONCLUSIONS

The findings support the hypothesis and have clinical relevance because, often, only brief rehabilitation may be available in the clinic and, thus, augmenting with a pharmacotherapy such as GAL may lead to outcomes that are significantly better than either therapy alone.

Comparable impediment of cognitive function in female and male rats subsequent to daily administration of haloperidol after traumatic brain injury

Antipsychotic drugs, such as haloperidol (HAL), are prescribed in the clinic to manage traumatic brain injury (TBI)-induced agitation. While preclinical studies have consistently shown that once-daily administration of HAL hinders functional recovery after TBI in male rats, its effects in females are unknown. Hence, the objective of this study was to directly compare neurobehavioral and histological outcomes in both sexes to determine whether the reported deleterious effects of HAL extend to females. Anesthetized adult female and male rats received either a controlled cortical impact (CCI) or sham injury and then were randomly assigned to a dosing regimen of HAL (0.5mg/kg, i.p.) or vehicle (VEH; 1mL/kg, i.p.) that was initiated 24h after injury and continued once daily for 19 consecutive days. Motor function was tested using established beam-balance/walk protocols on post-operative days 1-5 and acquisition of spatial learning was assessed with a well-validated Morris water maze task on days 14-19. Cortical lesion volume was quantified at 21days. No statistical differences were revealed between the HAL and VEH-treated sham groups and thus they were pooled for each sex. HAL only impaired motor recovery in males (p<0.05), but significantly diminished spatial learning in both sexes (p<0.05). Females, regardless of treatment, exhibited smaller cortical lesions vs VEH-treated males (p<0.05). Taken together, the data show that daily HAL does not prohibit motor recovery in females, but does negatively impact cognition. These task-dependent differential effects of HAL in female vs male rats may have clinical significance as they can direct therapy.

Refining environmental enrichment to advance rehabilitation based research after experimental traumatic brain injury

The typical environmental enrichment (EE) paradigm, which consists of continuous exposure after experimental traumatic brain injury (TBI), promotes behavioral and histological benefits. However, rehabilitation is often abbreviated in the clinic and administered in multiple daily sessions. While recent studies have demonstrated that a once daily 6-hr bout of EE confers benefits comparable to continuous EE, breaking the therapy into two shorter sessions may increase novelty and ultimately enhance recovery. Hence, the aim of the study was to test the hypothesis that functional and histological outcomes will be significantly improved by daily preclinical neurorehabilitation consisting of two 3-hr periods of EE vs. a single 6-hr session. Anesthetized adult male rats received a controlled cortical impact of moderate-to-severe injury (2.8mm tissue deformation at 4m/s) or sham surgery and were then randomly assigned to groups receiving standard (STD) housing, a single 6-hr session of EE, or two 3-hr sessions of EE daily for 3weeks. Motor function (beam-balance/traversal) and acquisition of spatial learning/memory retention (Morris water maze) were assessed on post-operative days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. Both EE conditions improved motor function and acquisition of spatial learning, and reduced cortical lesion volume relative to STD housing (p<0.05), but did not differ from one another in any endpoint (p>0.05). The findings replicate previous work showing that 6-hr of EE daily is sufficient to confer behavioral and histological benefits after TBI and extend the findings by demonstrating that the benefits are comparable regardless of how the 6-hrs of EE are accrued. The relevance of the finding is that it can be extrapolated to the clinic and may benefit patients who cannot endure a single extended period of neurorehabilitation.

Galantamine and Environmental Enrichment Enhance Cognitive Recovery after Experimental Traumatic Brain Injury But Do Not Confer Additional Benefits When Combined

Environmental enrichment (EE) enhances cognition after traumatic brain injury (TBI). Galantamine (GAL) is an acetylcholinesterase inhibitor that also may promote benefits. Hence, the aims of this study were to assess the efficacy of GAL alone (standard [STD] housing) and in combination with EE in adult male rats after TBI. The hypothesis was that both therapies would confer motor, cognitive, and histological benefits when provided singly, but that their combination would be more efficacious. Anesthetized rats received a controlled cortical impact or sham injury, then were randomly assigned to receive GAL (1, 2, or 3 mg/kg; intraperitoneally [i.p.]) or saline vehicle (VEH; 1 mL/kg; i.p.) beginning 24 h after surgery and once daily for 21 days (experiment 1). Motor (beam-balance/walk) and cognitive (Morris water maze [MWM]) assessments were conducted on post-operative Days 1-5 and 14-19, respectively. Cortical lesion volumes were quantified on Day 21. Sham controls were better versus all TBI groups. No differences in motor function or lesion volumes were observed among the TBI groups (p > 0.05). In contrast, GAL (2 mg/kg) enhanced MWM performance versus VEH and GAL (1 and 3 mg/kg; p < 0.05). In experiment 2, GAL (2 mg/kg) or VEH was combined with EE and the data were compared with the STD-housed groups from experiment 1. EE alone enhanced motor performance over the VEH-treated and GAL-treated (2 mg/kg) STD-housed groups (p < 0.05). Moreover, both EE groups (VEH or GAL) facilitated spatial learning and reduced lesion size versus STD + VEH controls (p < 0.05). No additional benefits were observed with the combination paradigm, which does not support the hypothesis. Overall, the data demonstrate that EE and once daily GAL (2 mg/kg) promote cognitive recovery after TBI. Importantly, the combined therapies did not negatively affect outcome and thus this therapeutic protocol may have clinical utility.

Abbreviated environmental enrichment confers neurobehavioral, cognitive, and histological benefits in brain-injured female rats

Environmental enrichment (EE) promotes behavioral recovery after experimental traumatic brain injury (TBI). However, the chronic rehabilitation provided in the laboratory is not analogous to the clinic where physiotherapy is typically limited. Moreover, females make up approximately 40% of the clinical TBI population, yet they are seldom studied in brain trauma. Hence, the goal of this study was to test the hypothesis that abbreviated EE would confer neurobehavioral, cognitive, and histological benefits in brain injured female rats. Anesthetized rats received a cortical impact of moderate-to-severe injury (2.8mm tissue deformation at 4m/s) or sham surgery and then were randomly assigned to groups receiving standard (STD) housing or 4h, 6h, or 24h of EE daily. Motor function (beam-balance/walk and rotarod) was assessed on post-operative days 1-5 and every other day from 1 to 19, respectively. Spatial learning/memory (Morris water maze) was evaluated on days 14-19, and cortical lesion volume was quantified on day 21. No statistical differences were appreciated among the sham controls in any assessment and thus the data were pooled. All EE conditions improved motor function and memory retention, but only 6h and 24h enhanced spatial learning relative to STD (p<0.05). Moreover, EE, regardless of duration reduced cortical lesion volume (p<0.05). These data confirm that abbreviated EE confers robust neurobehavioral, cognitive, and histological benefits in TBI female rats, which supports the hypothesis and strengthens the utility of EE as a pre-clinical model of neurorehabilitation.

Relative to Typical Antipsychotic Drugs, Aripiprazole Is a Safer Alternative for Alleviating Behavioral Disturbances After Experimental Brain Trauma

BACKGROUND

Antipsychotic drugs (APDs) are used to manage traumatic brain injury (TBI)-induced behavioral disturbances, such as agitation and aggression. However, APDs exhibiting D₂ receptor antagonism impede cognitive recovery after experimental TBI. Hence, empirical evaluation of APDs with different mechanistic actions is warranted. Aripiprazole (ARIP) is a D₂ and 5-hydroxytryptamine_1A (5-HT_1A) receptor agonist; pharmacotherapies with these properties enhance cognition after TBI.

OBJECTIVE

To test the hypothesis that ARIP would increase behavioral performance and decrease histopathology after TBI.

METHODS

Adult male rats were subjected to either a controlled cortical impact (CCI) or sham injury and then randomly assigned to ARIP (0.1 or 1.0 mg/kg) or VEH (1.0 mL/kg, saline vehicle) groups. Treatments began 24 hours after surgery and were administered once daily for 19 days. Motor (beam-balance/beam-walk) and cognitive (Morris water maze) performance was assessed on postoperative days 1 to 5 and 14 to 19, respectively, followed by quantification of hippocampal CA_1,3 neuron survival and cortical lesion volume.

RESULTS

Beam-balance was significantly improved in the CCI + ARIP (1.0 mg/kg) group versus CCI + ARIP (0.1 mg/kg) and CCI + VEH (P < .05). Spatial learning and memory retention were significantly improved in the CCI + ARIP (0.1 mg/kg) group versus the CCI + ARIP (1.0 mg/kg) and CCI + VEH groups (P < .05). Both doses of ARIP reduced lesion size and CA₃ cell loss versus VEH (P < .05). Importantly, neither dose of ARIP impeded functional recovery as previously reported with other APDs.

CONCLUSION

These findings support the hypothesis and endorse ARIP as a safer APD for alleviating behavioral disturbances after TBI.

The Therapeutic Efficacy of Environmental Enrichment and Methylphenidate Alone and in Combination after Controlled Cortical Impact Injury

Environmental enrichment (EE) and methylphenidate (MPH) independently confer significant benefit to behavioral recovery after controlled cortical impact (CCI) injury. Given that combinational therapies may be more clinically translatable than monotherapies, the aim of the current study was to test the hypothesis that a combined treatment regimen of EE and MPH would provide greater therapeutic efficacy than either one alone. Anesthetized adult male rats received either a CCI of moderate severity or sham injury and were then randomly assigned to EE or standard (STD) housing where they received either intraperitoneal (ip) MPH (5 mg/kg) or vehicle (VEH; 1.0 mL/kg; ip) beginning 24 h after injury and once daily for 19 days. Motor and cognitive assessments were conducted on post-injury days 1-5 and 14-19, respectively. No differences were observed in sham controls regardless of treatments, and thus their data were pooled. The traumatic brain injury (TBI)+EE+VEH and TBI+EE+MPH groups exhibited enhanced beam balance and beam walk performance relative to the TBI+STD+VEH group (p < 0.05), but did not differ from one another (p > 0.05). No effect of MPH treatment alone was observed in either motor task. In contrast, MPH improved spatial learning and memory when presented alone and also when combined with EE relative to VEH-treated STD controls (p < 0.05). In addition, both EE groups performed significantly better than the TBI+STD+MPH group (p < 0.05), but did not differ from one another (p > 0.05). These data replicate previous findings that both EE and MPH confer cognitive benefits after TBI and extend the findings by revealing that combining EE and MPH does not produce effects greater than either treatment alone, which does not support the hypothesis. The lack of an additive effect may be because of the robustness of the EE.

Combination therapies for neurobehavioral and cognitive recovery after experimental traumatic brain injury: Is more better?

Traumatic brain injury (TBI) is a significant health care crisis that affects two million individuals in the United Sates alone and over ten million worldwide each year. While numerous monotherapies have been evaluated and shown to be beneficial at the bench, similar results have not translated to the clinic. One reason for the lack of successful translation may be due to the fact that TBI is a heterogeneous disease that affects multiple mechanisms, thus requiring a therapeutic approach that can act on complementary, rather than single, targets. Hence, the use of combination therapies (i.e., polytherapy) has emerged as a viable approach. Stringent criteria, such as verification of each individual treatment plus the combination, a focus on behavioral outcome, and post-injury vs. pre-injury treatments, were employed to determine which studies were appropriate for review. The selection process resulted in 37 papers that fit the specifications. The review, which is the first to comprehensively assess the effects of combination therapies on behavioral outcomes after TBI, encompasses five broad categories (inflammation, oxidative stress, neurotransmitter dysregulation, neurotrophins, and stem cells, with and without rehabilitative therapies). Overall, the findings suggest that combination therapies can be more beneficial than monotherapies as indicated by 46% of the studies exhibiting an additive or synergistic positive effect versus on 19% reporting a negative interaction. These encouraging findings serve as an impetus for continued combination studies after TBI and ultimately for the development of successful clinically relevant therapies.

Combining the Antipsychotic Drug Haloperidol and Environmental Enrichment after Traumatic Brain Injury Is a Double-Edged Sword

Environmental enrichment (EE) confers significant benefits after experimental traumatic brain injury (TBI). In contrast, the antipsychotic drug (APD) haloperidol (HAL) exerts deleterious effects on neurobehavioral and cognitive recovery. Neurorehabilitation and management of agitation, however, are integral components of the treatment strategy for patients with TBI. Hence, the goal of this study was to determine how the two therapeutic approaches interact and influence motor and cognitive recovery. Anesthetized adult male rats received a controlled cortical impact (2.8 mm tissue deformation at 4 m/sec) or sham injury and then were provided HAL (0.5 mg/kg; intraperitoneally [IP]) or vehicle (VEH; 1 mL/kg; IP) commencing 24 h after surgery and once daily for 19 days while housed in EE or standard (STD) conditions. Beam balance/walk and Morris water maze performance were assessed on post-injury days 1-5 and 14-19, respectively, followed immediately by quantification of cortical lesion volumes. The data revealed both expected and unexpected findings. It was not surprising that the TBI groups receiving EE performed significantly better than those in STD housing and that the TBI + STD + HAL group performed worse than the TBI + STD + VEH group (p < 0.05). What was surprising was that the therapeutic effects of EE were greatly reduced by concomitant administration of HAL. No differences in cortical lesion volumes were observed among the groups (p > 0.05). The potential clinical implications of these findings suggest that administering HAL to patients undergoing neurorehabilitation may be a double-edged sword because agitation must be controlled before rehabilitation can be safely initiated and executed, but its use may compromise therapeutic efficacy.

Repetitive Mild Traumatic Brain Injury in the Developing Brain: Effects on Long-Term Functional Outcome and Neuropathology

Although accumulating evidence suggests that repetitive mild TBI (rmTBI) may cause long-term cognitive dysfunction in adults, whether rmTBI causes similar deficits in the immature brain is unknown. Here we used an experimental model of rmTBI in the immature brain to answer this question. Post-natal day (PND) 18 rats were subjected to either one, two, or three mild TBIs (mTBI) or an equivalent number of sham insults 24 h apart. After one or two mTBIs or sham insults, histology was evaluated at 7 days. After three mTBIs or sham insults, motor (d1-5), cognitive (d11-92), and histological (d21-92) outcome was evaluated. At 7 days, silver degeneration staining revealed axonal argyrophilia in the external capsule and corpus callosum after a single mTBI, with a second impact increasing axonal injury. Iba-1 immunohistochemistry showed amoeboid shaped microglia within the amygdalae bilaterally after mTBI. After three mTBI, there were no differences in beam balance, Morris water maze, and elevated plus maze performance versus sham. The rmTBI rats, however, showed impairment in novel object recognition and fear conditioning. Axonal silver staining was observed only in the external capsule on d21. Iba-1 staining did not reveal activated microglia on d21 or d92. In conclusion, mTBI results in traumatic axonal injury and microglial activation in the immature brain with repeated impact exacerbating axonal injury. The rmTBI in the immature brain leads to long-term associative learning deficit in adulthood. Defining the mechanisms damage from rmTBI in the developing brain could be vital for identification of therapies for children.

Found in translation: Understanding the biology and behavior of experimental traumatic brain injury

The aim of this review is to discuss in greater detail the topics covered in the recent symposium entitled "Traumatic brain injury: laboratory and clinical perspectives," presented at the 2014 International Behavioral Neuroscience Society annual meeting. Herein, we review contemporary laboratory models of traumatic brain injury (TBI) including common assays for sensorimotor and cognitive behavior. New modalities to evaluate social behavior after injury to the developing brain, as well as the attentional set-shifting test (AST) as a measure of executive function in TBI, will be highlighted. Environmental enrichment (EE) will be discussed as a preclinical model of neurorehabilitation, and finally, an evidence-based approach to sports-related concussion will be considered. The review consists predominantly of published data, but some discussion of ongoing or future directions is provided.

Divergent long-term consequences of chronic treatment with haloperidol, risperidone, and bromocriptine on traumatic brain injury-induced cognitive deficits

Antipsychotic drugs (APDs) are provided in the clinic to manage traumatic brain injury (TBI)-induced agitation and aggression. Experimental TBI studies consistently show that daily administration of the APDs, haloperidol (HAL) and risperidone (RISP), hinder recovery. However, it is unknown how long the adverse effects remain after cessation of treatment. To elucidate this clinically relevant issue, anesthetized male rats were randomly assigned to four TBI (controlled cortical impact) and four sham groups administered HAL (0.5 mg/kg), RISP (0.45 mg/kg), bromocriptine (BRO; 5.0 mg/kg, included as a control for D2 receptor action), or vehicle (VEH; 1 mL/kg) 24 h after surgery and once-daily for 19 days. Motor and cognitive recovery was assessed on days 1-5 and 14-19, respectively, and again at 1 and 3 months after drug withdrawal. No overall group differences were observed for motor function among the TBI groups, although the HAL group showed a greater beam-walk deficit on day 5 versus the VEH and BRO groups. Cognitive recovery was significantly impaired in the HAL and RISP groups during the treatment phase versus VEH and BRO. Further, BRO was superior to VEH (p=0.0042). At 1 month, both groups that received APDs continued to exhibit significant cognitive impairment versus VEH and BRO; at 3 months, only the HAL group was impaired. Moreover, the HAL, RISP, and VEH groups continued to be cognitively deficient versus BRO, which also reduced cortical damage. These data replicate previous reports that HAL and RISP impede cognitive recovery after TBI and expand the literature by revealing that the deleterious effects persist for 3 months after drug discontinuation. BRO conferred cognitive benefits when administered concomitantly with behavioral testing, thus replicating previous findings, and also after cessation demonstrating enduring efficacy.

Emerging therapies in traumatic brain injury

Despite decades of basic and clinical research, treatments to improve outcomes after traumatic brain injury (TBI) are limited. However, based on the recent recognition of the prevalence of mild TBI, and its potential link to neurodegenerative disease, many new and exciting secondary injury mechanisms have been identified and several new therapies are being evaluated targeting both classic and novel paradigms. This includes a robust increase in both preclinical and clinical investigations. Using a mechanism-based approach the authors define the targets and emerging therapies for TBI. They address putative new therapies for TBI across both the spectrum of injury severity and the continuum of care, from the field to rehabilitation. They discussTBI therapy using 11 categories, namely, (1) excitotoxicity and neuronal death, (2) brain edema, (3) mitochondria and oxidative stress, (4) axonal injury, (5) inflammation, (6) ischemia and cerebral blood flow dysregulation, (7) cognitive enhancement, (8) augmentation of endogenous neuroprotection, (9) cellular therapies, (10) combination therapy, and (11) TBI resuscitation. The current golden age of TBI research represents a special opportunity for the development of breakthroughs in the field.

A combined therapeutic regimen of buspirone and environmental enrichment is more efficacious than either alone in enhancing spatial learning in brain-injured pediatric rats

Buspirone, a 5-HT1A receptor agonist, and environmental enrichment (EE) enhance cognition and reduce histopathology after traumatic brain injury (TBI) in adult rats, but have not been fully evaluated after pediatric TBI, which is the leading cause of death in children. Hence, the aims of this study were to assess the efficacy of buspirone alone (Experiment 1) and in combination with EE (Experiment 2) in TBI postnatal day-17 male rats. The hypothesis was that both therapies would confer cognitive and histological benefits when provided singly, but their combination would be more efficacious. Anesthetized rats received a cortical impact or sham injury and then were randomly assigned to receive intraperitoneal injections of buspirone (0.08 mg/kg, 0.1 mg/kg, and 0.3 mg/kg) or saline vehicle (1.0 mL/kg) 24 h after surgery and once daily for 16 days (Experiment 1). Spatial learning and memory were assessed using the Morris water maze (MWM) on post-operative days 11-16, and cortical lesion volume was quantified on day 17. Sham controls for each condition were significantly better than all TBI groups. In the TBI groups, buspirone (0.1 mg/kg) enhanced MWM performance versus vehicle and buspirone (0.08 mg/kg and 0.3 mg/kg) (p<0.05) and reduced lesion volume relative to vehicle (p=0.038). In Experiment 2, buspirone (0.1 mg/kg) or vehicle was combined with EE after TBI, and the data were compared to the standard (STD)-housed groups from Experiment 1. EE lead to a significant enhancement of spatial learning and a reduction in lesion size versus STD. Moreover, the combined treatment group (buspirone+EE) performed markedly better than the buspirone+STD and vehicle+EE groups, which suggests an additive effect and supports the hypothesis. The data replicate previous studies assessing these therapies in adult rats. These novel findings may have important rehabilitation-relevant implications for clinical pediatric TBI.

Environmental enrichment as a viable neurorehabilitation strategy for experimental traumatic brain injury

Environmental enrichment (EE) emerged as a robust independent variable capable of influencing behavioral outcome in experimental studies after the fortuitous observation by renowned neuropsychologist Donald O. Hebb that rats raised as pets in his home performed markedly better on problem-solving tasks than those kept in the laboratory. In the subsequent years, numerous studies ensued demonstrating that EE was also capable of inducing neuroplasticity in normal (i.e., noninjured) rats. These behavioral and neural alterations provided the impetus for investigating EE as a potential therapy for traumatic brain injury (TBI), which, over the past two decades, has resulted in several reports. Hence, the aim of this review is to integrate the findings and present the current state of EE as a viable neurorehabilitation strategy for TBI. Using the specific key term searches "traumatic brain injury" and "environmental enrichment" or "enriched environment," 30 and 30 experimental TBI articles were identified by PubMed and Scopus, respectively. Of these, 27 articles were common to both search engines. An additional article was found on PubMed using the key terms "enriched environment" and "fluid percussion." A review of the bibliographies in the 34 articles did not yield additional citations. The overwhelming consensus of the 34 publications is that EE benefits behavioral and histological outcome after brain injury produced by various models. Further, the enhancements are observed in male and female as well as adult and pediatric rats and mice. Taken together, these cumulative findings provide strong support for EE as a generalized and robust preclinical model of neurorehabilitation. However, to further enhance the model and to more accurately mimic the clinic, future studies should continue to evaluate EE during more rehabilitation-relevant conditions, such as delayed and shorter time periods, as well as in combination with other therapeutic approaches, as we have been doing for the past few years.

Old dog, new tricks: the attentional set-shifting test as a novel cognitive behavioral task after controlled cortical impact injury

Cognitive impairment associated with prefrontal cortical dysfunction is a major component of disability in traumatic brain injury (TBI) survivors. Specifically, deficits of cognitive flexibility and attentional set-shifting are present across all levels of injury severity. Though alterations in spatial learning have been extensively described in experimental models of TBI, studies investigating more complex cognitive deficits are relatively scarce. Hence, the aim of this preclinical study was to expand on this important issue by evaluating the effect of three injury levels on executive function and behavioral flexibility performance as assessed using an attentional set-shifting test (AST). Isoflurane-anesthetized male rats received a controlled cortical impact (CCI) injury (2.6, 2.8, and 3.0 mm cortical depth at 4 m/sec) or sham injury, whereas an additional group had no surgical manipulation (naïve). Four weeks postsurgery, rats were tested on the AST, which involved a series of discriminative tasks of increasing difficulty, such as simple and compound discriminations, stimulus reversals, and intra- and extradimensional (ED) shifts. TBI produced accompanying impact depth-dependent increases in cortical lesion volumes, with the 3.0-mm cortical depth group displaying significantly larger injury volumes than the 2.6-mm group (p=0.05). Further, injury severity-induced deficits in ED set-shifting and stimulus reversals, as well as increases in total response error rates and total set loss errors, were observed. These novel findings demonstrate executive function and behavioral flexibility deficits in our animal model of CCI injury and provide the impetus to integrate the AST in the standard neurotrauma behavioral battery to further evaluate cognitive dysfunction after TBI. Ongoing experiments in our laboratory are assessing AST performance after pharmacological and rehabilitative therapies post-TBI, as well as elucidating possible mechanisms underlying the observed neuropsychological deficits.

Donepezil is ineffective in promoting motor and cognitive benefits after controlled cortical impact injury in male rats

The acetylcholinesterase (AChE) inhibitor donepezil is used as a therapy for Alzheimer's disease and has been recommended as a treatment for enhancing attention and memory after traumatic brain injury (TBI). Although select clinical case studies support the use of donepezil for enhancing cognition, there is a paucity of experimental TBI studies assessing the potential efficacy of this pharmacotherapy. Hence, the aim of this pre-clinical study was to evaluate several doses of donepezil to determine its effect on functional outcome after TBI. Ninety anesthetized adult male rats received a controlled cortical impact (CCI; 2.8 mm cortical depth at 4 m/sec) or sham injury, and then were randomly assigned to six TBI and six sham groups (donepezil 0.25, 0.5, 1.0, 2.0, or 3.0 mg/kg, and saline vehicle 1.0 mL/kg). Treatments began 24 h after surgery and were administered i.p. once daily for 19 days. Function was assessed by motor (beam balance/walk) and cognitive (Morris water maze) tests on days 1-5 and 14-19, respectively. No significant differences were observed among the sham control groups in any evaluation, regardless of dose, and therefore the data were pooled. Furthermore, no significant differences were revealed among the TBI groups in acute neurological assessments (e.g., righting reflex), suggesting that all groups received the same level of injury severity. None of the five doses of donepezil improved motor or cognitive function relative to vehicle-treated controls. Moreover, the two highest doses significantly impaired beam-balance (3.0 mg/kg), beam-walk (2.0 mg/kg and 3.0 mg/kg), and cognitive performance (3.0 mg/kg) versus vehicle. These data indicate that chronic administration of donepezil is not only ineffective in promoting functional improvement after moderate CCI injury, but depending on the dose is actually detrimental to the recovery process. Further work is necessary to determine if other AChE inhibitors exert similar effects after TBI.

The effect of environmental enrichment on substantia nigra gene expression after traumatic brain injury in rats

Experimental investigations into the effects of traumatic brain injury (TBI) have demonstrated significant alterations in dopaminergic systems. Dopaminergic fibers originating within the substantia nigra and ventral tegmental area (VTA) are important for reward learning, addiction, movement, and behavior. However, little is known about the effect of TBI on substantia nigra and VTA function. Environmental enrichment (EE) has been shown to improve functional outcome after TBI, and a number of studies suggest that it may exert some benefits via dopaminergic signaling. To better understand the role of dopamine in chronic TBI pathophysiology and the effect of EE, we examined the mRNA expression profile within the substantia nigra and VTA at 4 weeks post-injury. Specifically, three comparisons were made: 1) TBI versus sham, 2) sham+EE versus sham+standard (STD) housing, and 3) TBI+EE versus TBI+STD. There were differential expressions of 25, 4, and 40 genes in these comparisons, respectively. Chronic alterations in genes post-injury within the substantia nigra and VTA included genes important for cellular membrane homeostasis and transcription. EE-induced gene alterations after TBI included genes important for signal transduction, in particular calcium signaling pathways, membrane homeostasis, and metabolism. Elucidation of these alterations in gene expression within the substantia nigra and VTA provides new insights into chronic changes in dopamine signaling post-TBI, and the potential role of EE in TBI rehabilitation.

Environmental enrichment promotes robust functional and histological benefits in female rats after controlled cortical impact injury

Environmental enrichment (EE) consistently induces marked benefits in male rats after traumatic brain injury (TBI), but whether similar efficacy extends to females is not well established. Hence, the aim of this study was to reassess the effect of EE on functional and histological outcome in female rats after brain trauma. Twenty-four normal cycling adult female rats underwent verification of estrous stage prior to controlled cortical impact (CCI) or sham injury and then were assigned to EE or standard (STD) housing. Motor function was assessed with beam-balance/beam-walk and rotarod tasks on post-operative days 1-5 and every other day from 1-19, respectively. Spatial learning/memory was evaluated in a Morris water maze on days 14-19. Morphologically intact hippocampal CA(1/3) cells and cortical lesion volume were quantified 3 weeks after injury. No differences were observed between the EE and STD sham groups in any endpoint measure and thus the data were pooled. In the TBI groups, EE improved beam-balance, beam-walk, rotarod, and spatial learning performance vs. STD (p's<0.05). EE also provided significant histological protection as confirmed by increased CA(1/3) cell survival and decreased cortical lesion size vs. STD. These data demonstrate that EE confers robust benefits in female rats after CCI injury, which parallels numerous studies in males and lends further credence for EE as a preclinical model of neurorehabilitation.